A few ideas on loadouts:
Standard Load:
8th: Mind Blank (can't scry me!) (swap out for Planar Binding, Greater, on "work" days)
7th: Magnificent Mansion (Safe resting point - unless someone is playing around with Gate, or gets access to a tuning fork for his mansion or something), some offensive or utility spell
6th: Contingency (Resilient Sphere) (hit me for damage, and I get resting time! - well, unless someone has a readied action to get rid of it with a Disintigrate or something before my next turn), Mass Suggestion ("He has betrayed you all!" or "No, no, no ... you like me, I'm an old friend of yours" or something), Mislead (See Me? I'm running North.... while I run south, invisibly)
5th: Teleport (for getting away), Mage's Private Sanctum (in conjuction with Magnificient Mansion - very safe resting point; can't even scry your Planar Bound "guests") ,two offensive or utility spells for flavor
4th: Dimension Door (for a short hop or two), Resilient Sphere (slot reserved for Contingency), Mass Reduce Person (for the grapple penalty), Black Tentacles (for the grapple), Something for a bonus slot - the Int is at least 18, right?
3rd: don't much care at this point - won't usually be worth the time - assume he puts whatever he needs here for the day
On working days, he stays in his Mansion full time, and either crafts stuff, researches spells, or calls up Planar Bindings (flavor dependent, mostly - do you want him having lots of demons to throw at his enemies, golems, odd items, or unique spells?)
Unless his type is such that he doesn't need it, he will likely want a Ring of Sustenence (may have to buy, commision, or steal it), a Neclace of Adaptation, perhaps a Portable Hole (Player: "where could he have possibly gone? He's out of spells!" DM "Make a spot check..."), a spare spellbook with his common load, plus Plane Shift, engraved inside. He will also want a Mithral Buckler (no ASF or ACP, so profieciency doesn't matter) with a Permanencied Symbol of Persuasion (sight-triggered) or two (You see him! He's holding a shield! Save or be charmed!).